Variable-wedge rotating-disk beam attenuator for ophthalmic endoilluminator

ABSTRACT

A variable-wedge rotating-disk attenuator for use in an ophthalmic endoilluminator is disclosed. The attenuator includes a wedge attached to an axle. The size of the wedge can be adjusted over a variable angle as measured through an arc of the wedge. The axle to which the wedge is attached rotates such that the wedge rotates around a pivot defined by the axle. The variable-wedge rotating-disk attenuator is located such that it affects the intensity of a light beam transmitted into an eye.

BACKGROUND OF THE INVENTION

The present invention relates to an illuminator for use in ophthalmicsurgery and more particularly to ophthalmic illuminator utilizing avariable-wedge rotating-disk attenuator to produce a light suitable forilluminating the inside of the eye.

Anatomically, the eye is divided into two distinct parts—the anteriorsegment and the posterior segment. The anterior segment includes thelens and extends from the outermost layer of the cornea (the cornealendothelium) to the posterior of the lens capsule. The posterior segmentincludes the portion of the eye behind the lens capsule. The posteriorsegment extends from the anterior hyaloid face to the retina, with whichthe posterior hyaloid face of the vitreous body is in direct contact.The posterior segment is much larger than the anterior segment.

The posterior segment includes the vitreous body—a clear, colorless,gel-like substance. It makes up approximately two-thirds of the eye'svolume, giving it form and shape before birth. It is composed of 1%collagen and sodium hyaluronate and 99% water. The anterior boundary ofthe vitreous body is the anterior hyaloid face, which touches theposterior capsule of the lens, while the posterior hyaloid face formsits posterior boundary, and is in contact with the retina. The vitreousbody is not free-flowing like the aqueous humor and has normal anatomicattachment sites. One of these sites is the vitreous base, which is a3-4 mm wide band that overlies the ora serrata. The optic nerve head,macula lutea, and vascular arcade are also sites of attachment. Thevitreous body's major functions are to hold the retina in place,maintain the integrity and shape of the globe, absorb shock due tomovement, and to give support for the lens posteriorly. In contrast toaqueous humor, the vitreous body is not continuously replaced. Thevitreous body becomes more fluid with age in a process known assyneresis. Syneresis results in shrinkage of the vitreous body, whichcan exert pressure or traction on its normal attachment sites. If enoughtraction is applied, the vitreous body may pull itself from its retinalattachment and create a retinal tear or hole.

Various surgical procedures, called vitreo-retinal procedures, arecommonly performed in the posterior segment of the eye. Vitreo-retinalprocedures are appropriate to treat many serious conditions of theposterior segment. Vitreo-retinal procedures treat conditions such asage-related macular degeneration (AMD), diabetic retinopathy anddiabetic vitreous hemorrhage, macular hole, retinal detachment,epiretinal membrane, CMV retinitis, and many other ophthalmicconditions.

A surgeon performs vitreo-retinal procedures with a microscope andspecial lenses designed to provide a clear image of the posteriorsegment. Several tiny incisions just a millimeter or so in length aremade on the sclera at the pars plana. The surgeon inserts microsurgicalinstruments through the incisions such as a fiber optic light source toilluminate inside the eye, an infusion line to maintain the eye's shapeduring surgery, and instruments to cut and remove the vitreous body.

During such surgical procedures, proper illumination of the inside ofthe eye is important. Typically, a thin optical fiber is inserted intothe eye to provide the illumination. A light source, such as a metalhalide lamp, a halogen lamp, a xenon lamp, or a mercury vapor lamp, isoften used to produce the light carried by the optical fiber into theeye. Since such lamps cannot be easily dimmed while maintaining outputperformance and color balance, they are run at full power, and lightintensity is varied by mechanical means. In varying the intensity of thelight beam, it is important to maintain the beam diameter and onlydecrease the intensity of the beam. The light beam, whether attenuatedor not, must be focused and aligned with the optical fiber that carriesthe beam into the eye.

Traditionally, the intensity of the light is varied by using mechanicallouvers, camera variable aperture mechanisms, or neutral densityfilters. A mechanical louver operates like a set of Venetian blinds. Thelouvers are opened a certain amount to allow a certain amount of lightto pass through. Such louvers, however, produce a series of bright anddark stripes in the resulting light beam. These can result in rings andother angular non-uniformities that appear in the beam emitted from theoptical fiber. These non-uniformities deteriorate the quality ofintraocular illumination. Likewise, the use of mechanical variableaperture mechanisms can also cause angular non-uniformities and anundesired narrowing of the width of the beam exiting the distal end ofthe fiber. Neutral density filters are often made of glass and blockunwanted light. As they block light, they can heat up and crack. What isneeded is an attenuator that does not decrease the diameter of the lightbeam or produce non-uniformities.

SUMMARY OF THE INVENTION

In one embodiment consistent with the principles of the presentinvention, the present invention is a variable-wedge rotating-diskattenuator for use in an ophthalmic endoilluminator. The attenuatorincludes a wedge attached to an axle. The size of the wedge can beadjusted over a variable angle as measured through an arc of the wedge.The axle to which the wedge is attached rotates such that the wedgerotates around a pivot defined by the axle. The variable-wedgerotating-disk attenuator is located such that it affects the intensityof a light beam transmitted into an eye.

In another embodiment consistent with the principles of the presentinvention, the present invention is a variable-wedge rotating-diskattenuator for use in an ophthalmic endoilluminator. The variable-wedgerotating-disk attenuator includes first and second spines. Theapproximate center of both spines is located at a pivot point. Thespines can be rotated independently. A substantially optically opaquematerial is located between the first and second spines to form twowedges, each of which is capable of being adjusted. The wedges arelocated such that they attenuate the intensity of a light beamtransmitted into an eye.

In another embodiment consistent with the principles of the presentinvention, the present invention is a variable-wedge rotating-diskattenuator for use in an ophthalmic endoilluminator. The attenuator hasfirst and second spines. The approximate center of both spines islocated at a pivot point. The spines can be rotated independently. Asubstantially optically opaque material is located between the first andsecond spines to form two wedges, each of which is capable of beingadjusted. A first axle attached to the first spine is located along aline containing the pivot point that is substantially perpendicular tothe first spine. A second axle attached to the second spine is locatedalong a line containing the pivot point that is substantiallyperpendicular to the second spine. A first motor connected to the firstaxle rotates the first axle. A second motor connected to the second axlerotates the second axle. A controller controls the operation of thefirst and second motors. The controller operates the first and secondmotors at the same rotation rate but out of phase with each other tocause the variable-wedge rotating-disk attenuator to affect theintensity of a light beam transmitted into an eye.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are intended to provide further explanation of the invention asclaimed. The following description, as well as the practice of theinvention, set forth and suggest additional advantages and purposes ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate several embodiments of theinvention and together with the description, serve to explain theprinciples of the invention.

FIG. 1 is an unfolded view of an ophthalmic endoilluminator according toan embodiment of the present invention.

FIGS. 2A-2D are various views of a variable-wedge rotating-diskattenuator according to an embodiment of the present invention.

FIGS. 3A-3D are various views of a variable-wedge rotating-diskattenuator according to an embodiment of the present invention.

FIG. 4 is a cross section view of an ophthalmic endoilluminator locatedin an eye according to an embodiment of the present invention.

FIG. 5 depicts a variable-wedge rotating-disk attenuator with fourwedges according to an embodiment of the present invention.

FIG. 6 depicts a propeller blade and a triangular blade that can beutilized with a variable-wedge rotating-disk attenuator with four wedgesaccording to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference is now made in detail to the exemplary embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers are usedthroughout the drawings to refer to the same or like parts.

FIG. 1 is an unfolded view of an ophthalmic endoilluminator according toan embodiment of the present invention. In FIG. 1, the endoilluminatorincludes light source 105, collimating lens 110, optional cold mirror115, optional hot mirror 116, attenuator 120, condensing lens 125,connector 150, optical fiber 155, hand piece 160, and probe 165.

The light from light source 105 is collimated by collimating lens 110.The collimated light is reflected and filtered by optional cold mirror115 and/or optional hot mirror 116. The resulting beam is attenuated byattenuator 120 and focused by condensing lens 125. The focused beam isdirected through connector 150 and optical fiber 155 to probe 165 whereit illuminates the inside of the eye.

Light source 105 is typically a lamp, such as a mercury vapor lamp, axenon lamp, a metal halide lamp, or a halogen lamp. Light source 105 isoperated at or near full power to produce a relatively stable andconstant light output. Other embodiments of the present inventionutilize other light sources such as light emitting diodes (LEDs). One ormore LEDs can be operated to produce a constant and stable light output.As is known, there are many types of LEDs with different power ratingsand light output that can be selected as light source 105.

Collimating lens 110 is configured to collimate the light produced bylight source 105. As is commonly known, collimation of light involveslining up light rays. Collimated light is light whose rays are parallelwith a planar wave front. Other collimating elements, besidescollimating lens 110 may also be employed. For example, an asphericlens, a set of spherical lenses, or a hybrid refractive-diffractive lensmay be used to collimate light.

Optional cold mirror 115 is a dichroic reflector that reflects visiblewavelength light and only transmits infrared and ultraviolet light toproduce a beam filtered of harmful infrared and ultraviolet rays.Optional hot mirror 116 reflects long wavelength infrared light andshort wavelength ultraviolet light while transmitting visible light. Theeye's natural lens filters the light that enters the eye. In particular,the natural lens absorbs blue and ultraviolet light which can damage theretina. Providing light of the proper range of visible light wavelengthswhile filtering out harmful short and long wavelengths can greatlyreduce the risk of damage to the retina through aphakic hazard, bluelight photochemical retinal damage and infrared heating damage, andsimilar light toxicity hazards. Typically, a light in the range of about430 to 700 nanometers is preferable for reducing the risks of thesehazards. Optional cold mirror 115 and optional hot mirror 116 selectedto allow light of a suitable wavelength to be emitted into an eye. Otherfilters and/or dichroic beam splitters may also be employed to produce alight in this suitable wavelength range. For example, holographicmirrors may also be used to filter light.

Attenuator 120 attenuates or decreases the intensity of the light beamas more fully described in the following Figures.

Condensing lens 125 focuses the attenuated light beam so that it can belaunched in to a small gauge optical fiber. Condensing lens 125 is alens of suitable configuration for the system. Condensing lens 125 istypically designed so that the resulting focused beam of light can besuitably launched into and transmitted by an optical fiber. As iscommonly known, a condensing lens may be a biconvex or a plano-convexaspheric lens where one surface is planar and the other surface isconvex with a precise aspheric surface in order to focus the light to aminimum diameter spot. In addition, condensing lens may also be a hybridrefractive-diffractive lens.

The endoilluminator that is handled by the ophthalmic surgeon includesconnector 150, optical fiber 155, hand piece 160, and probe 165.Connector 150 is designed to connect the optical fiber 155 to a mainconsole (not shown) containing light source 105. Connector 150 properlyaligns optical fiber 155 with the beam of light that is to betransmitted into the eye. Optical fiber 155 is typically a small gaugefiber that may or may not be tapered. Hand piece 160 is held by thesurgeon and allows for the manipulation of probe 165 in the eye. Probe165 is inserted into the eye and carries optical fiber 155 whichterminates at the end of probe 165. Probe 165 thus provides illuminationfrom optical fiber 155 in the eye.

FIG. 2A is a view of a variable-wedge rotating-disk attenuator accordingto an embodiment of the present invention. Attenuator 120 includes avariable wedge 210 of an angle “a” that rotates around pivot 215.Variable wedge 210 is bounded by two spines 220 and 225. These twospines 220 and 225 support opaque material that makes up variable wedge210. Light beam 205 is depicted as well. While variable wedge 210 isdepicted as being pie-shaped, it can be of any convenient shape, suchas, for example, a triangle.

Variable wedge 210 can be adjusted so that angle “a” is in the range ofnearly zero degrees to 360 degrees. In one embodiment, variable wedge210 operates like a Japanese fan that can be opened to form a completedisc or closed to form a very narrow wedge. Variable wedge 210 typicallyincludes segmented members (located between spines 220 and 225 in FIG.2A) that can be folded together to decrease angle “a” or unfolded toincrease angle “a.” These members of variable wedge 210 are made of asubstantially optically opaque material designed to block light. Thismaterial may block 100% of the light or less than 100% of the light.

Variable wedge 210 is attached to a rotating axle, the end of which isseen as pivot 215. The axle and attached variable wedge 210 is rotatedrapidly so as to periodically occlude beam 205. The variable wedge 210is rotated more rapidly than the human eye can see, typically at a rateof greater than sixty times per second. Beam 205 is attenuated inproportion to the size of variable wedge 210. The greater the angle “a,”the more attenuation occurs.

A controller (not shown) controls the operation of the variable-wedgerotating-disk attenuator 120, a power supply (not shown) provides powerto operate the variable-wedge rotating-disk attenuator 120, and a motor(not shown) rotates the axle. The controller controls the operation ofthe various components of the system and is typically an integratedcircuit with power, input, and output pins capable of performing logicfunctions. In various embodiments, the controller is a targeted devicecontroller performing specific control functions targeted to a specificdevice or component, such as directing the operation of thevariable-wedge rotating-disk attenuator 120. In other embodiments, thecontroller is a programmable microprocessor. Software loaded into themicroprocessor implements the control functions provided by thecontroller. The controller may be made of many different components orintegrated circuits. The power supply may be, for example, a switch modepower supply or other type of power supply.

Using variable wedge 210 to attenuate light beam 205 eliminates thenon-uniformities produced by prior art means of attenuation. Variablewedge 210 occludes light beam 205 and therefore does not reduce itsdiameter. In addition, variable wedge 210 does not produce striations orlines in light beam 205. As such, the resulting intraocular light is ofa higher quality.

FIGS. 2B and 2C are two different views of the variable-wedgerotating-disk attenuator of FIG. 2A according to an embodiment of thepresent invention. In FIG. 2B variable wedge 210, denoted by the shadedarea, is small (angle “a” is small), and in FIG. 2C, variable wedge 210,denoted by the shaded area, is large (angle “a” is large). In FIG. 2B,light beam 205 is minimally occluded, and in FIG. 2C, light beam isalmost totally occluded. In this manner, angle “a” can be adjusted tovary the size of variable wedge 210 to produce almost no attenuation upto a complete attenuation of light beam 205. The resulting intraocularlight can thus be varied from no light to a maximum light.

FIG. 2D shows a top view of the variable wedge attenuator of FIGS.2A-2C. In FIG. 2D, spines 220 and 225 support opaque material members250 that form the various segments of the fan-like structure of variablewedge 210. Axle 235 is connected to spine 220 at a substantially rightangle. Likewise, axle 245 is connected to spine 225 at a substantiallyright angle. Axles 235 and 245 are connected to and driven by motors 230and 240, respectively. In this manner, motor 230 rotates axle 235 whichin turn drives spine 220 in a circular direction, and motor 240 rotatesaxle 245 which in turn drives spine 225 in a circular direction. Motors230 and 240 are synchronized but out of phase. In other words, bothmotors 230 and 240 are driven at the same rotational rate of speed,while the phase angle between them corresponds to angle “a”—the anglebetween spines 220 and 225. A controller (not shown) as described abovecontrols the operation of motors, 230 and 240.

FIGS. 3A-3D depict a variable-wedge rotating-disk attenuator with twowedges according to an embodiment of the present invention. Thestructure and operation of the embodiment of FIGS. 3A-3D is similar tothat of FIGS. 2A-2D. In FIG. 3A, attenuator 120 includes two variablewedges, 310 and 315, each of angle “a.” These two wedges are locatedopposite each other with respect to pivot 320 and rotate around pivot320. Variable wedges 310 and 315 are bounded by two spines 325 and 330.The approximate center of each spine is located at pivot 320. These twospines 325 and 330 support opaque material that makes up variable wedges310 and 315. Light beam 305 is depicted as well. While variable wedges310 and 315 are depicted as being pie-shaped, they can be of anyconvenient shape, such as, for example, a triangle.

Variable wedges 310 and 315 can be adjusted so that angle “a” is in therange of nearly zero degrees to 360 degrees. In one embodiment, variablewedges 310 and 315 operate like a Japanese fan that can be opened toform a complete disc or closed to form a very narrow wedge. Variablewedges 310 and 315 typically include segmented members (located betweenspines 325 and 330) that can be folded together to decrease angle “a” tonearly zero degrees or unfolded to increase angle “a” to 180 degrees.These members of variable wedges 310 and 315 are made of a substantiallyoptically opaque material designed to block light. This material mayblock 100% of the light or less than 100% of the light.

Variable wedges 310 and 315 are attached to a rotating axle, the end ofwhich is seen as pivot 320. The axle and attached variable wedges 310and 315 are rotated rapidly so as to periodically occlude beam 305. Thevariable wedges 310 and 315 are rotated more rapidly than the human eyecan see, typically at a rate of greater than sixty times per second.Beam 305 is attenuated in proportion to the size of the variable wedges310 and 315. The greater the angle “a,” the more attenuation occurs.

A controller (not shown) controls the operation of the variable-wedgerotating-disk attenuator 120, a power supply (not shown) provides powerto operate the variable-wedge rotating-disk attenuator 120, and a motor(not shown) rotates the axle. The controller controls the operation ofthe various components of the system and is typically an integratedcircuit with power, input, and output pins capable of performing logicfunctions. In various embodiments, the controller is a targeted devicecontroller performing specific control functions targeted to a specificdevice or component, such as directing the operation of thevariable-wedge rotating-disk attenuator 120. In other embodiments, thecontroller is a programmable microprocessor. Software loaded into themicroprocessor implements the control functions provided by thecontroller. The controller may be made of many different components orintegrated circuits. The power supply may be, for example, a switch modepower supply or other type of power supply.

Using variable wedges 310 and 315 to attenuate light beam 305 eliminatesthe non-uniformities produced by prior art means of attenuation.Variable wedges 310 and 315 occlude light beam 305 and therefore do notreduce its diameter. In addition, variable wedges 310 and 315 do notproduce striations or lines in light beam 305. As such, the resultingintraocular light is of a higher quality.

FIGS. 3B and 3C are two different views of the variable-wedgerotating-disk attenuator of FIG. 3A according to an embodiment of thepresent invention. In FIG. 3B variable wedges 310 and 315, denoted bythe shaded area, are small (angle “a” is small), and in FIG. 3C,variable wedges 310 and 315, denoted by the shaded area, are large(angle “a” is large). In FIG. 3B, light beam 305 is minimally occluded,and in FIG. 3C, light beam is almost totally occluded. In this manner,angle “a” can be adjusted to vary the size of variable wedges 310 and315 to produce almost no attenuation up to a complete attenuation oflight beam 305. The resulting intraocular light can thus be varied fromno light to a maximum light.

FIG. 3D shows a top view of the variable wedge attenuator of FIGS.3A-3C. In FIG. 3D, spines 325 and 330 support opaque material members360 that form the various segments of the fan-like structure of variablewedges 310 and 315. Axle 345 is connected to spine 325 at asubstantially right angle. Likewise, axle 355 is connected to spine 330at a substantially right angle. Axles 345 and 355 are aligned with pivot320. Axles 345 and 355 are connected to and driven by motors 340 and350, respectively. In this manner, motor 340 rotates axle 345 which inturn drives spine 325 in a circular direction, and motor 350 rotatesaxle 355 which in turn drives spine 330 in a circular direction. Motors340 and 350 are synchronized but out of phase. In other words, bothmotors 340 and 350 are driven at the same rotational rate of speed,while the phase angle between them corresponds to angle “a”—the anglebetween spines 325 and 330. A controller (not shown) as described abovecontrols the operation of motors 340 and 350.

The embodiment of FIGS. 3A-3D is balanced around pivot 320. In otherwords, the mass of variable wedge 310 is roughly equal to the mass ofvariable wedge 315. Variable wedge 310 is also located opposite variablewedge 315. When driven by motors 340 and 350, the attenuator is abalanced system.

Other numbers of variable wedges can be utilized in the same mannerdescribed in FIGS. 3A-3D. For example, Attenuator 120 may include three,four, or any number of wedges equally spaced around pivot 320. Threewedges require three spines; four wedges require four spines, etc. Thenumber of wedges is limited only by the physical space requirements fora given system. These multiple wedge attenuators can be operated in thesame manner as that described in FIGS. 3A-3D. For example, in a fourwedge system with four spines, two spines can be disposed at rightangles to each other and driven by one motor, while the other two spinescan be disposed at right angles to each other and driven by the othermotor.

For example, in FIG. 5, four variable wedges 510, 515, 520, and 525 areemployed in attenuator 120. Light beam 505 is partially occluded byvariable wedges 515 and 525. Variable wedges 510 and 515 are bounded byspines 540 and 545 and have the same angle “a.” Likewise, variablewedges 520 and 525 are bounded by spines 550 and 555 and have the sameangle “b.” Spine 545 is arranged to be at a substantially right angle tospine 550. Likewise, spine 540 is arranged to be at a substantiallyright angle to spine 555. Spines 545 and 550 can be connected via anaxle to one motor, and spines 540 and 555 can be connected to viaanother axle to another motor. The axles can be aligned with pivot point530. The attenuator 120 of FIG. 5 can be operated in the same manner asthe attenuator in FIG. 3A.

In addition to a wedge design, FIG. 6 depicts a propeller and a trianglethat can be implemented in attenuator 120. The blades of the propellercan be rotated about the central pivot point as well as about an axisdenoted by the dashed line. In this manner, the propeller blades can befixed at an angle with respect to the dashed line (like the blades of anairplane propeller or a ceiling fan) to occlude a certain percentage ofthe light beam. This angle can be varied to occlude more or less light.The same principle can be used for other shapes, such as the triangle.These propellers and triangular blades can be used as wedges or variablewedges in the present invention.

FIG. 4 is cross section view of an ophthalmic endoilluminator located inan eye according to an embodiment of the present invention. FIG. 4depicts hand piece 160 and probe 165 in use. Probe 165 is inserted intoeye 400 through an incision in the pars plana region. Probe 165illuminates the inside or vitreous region 405 of eye 400. In thisconfiguration, probe 165 can be used to illuminate the inside orvitreous region 405 of eye 400 during vitreo-retinal surgery.

From the above, it may be appreciated that the present inventionprovides an improved system for illuminating the inside of the eye. Thepresent invention provides a light source that can be attenuated withoutdistortion or a reduction in beam size to provide a light suitable forilluminating the inside of an eye. A variable-wedge rotating-diskattenuator is operated to alter the intensity of the light beam enteringthe eye without causing unwanted non-uniformities. The present inventionis illustrated herein by example, and various modifications may be madeby a person of ordinary skill in the art.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

1.-5. (canceled)
 6. A variable-wedge rotating-disk attenuator for use inan ophthalmic endoilluminator comprising: a wedge whose size is capableof being adjusted over a variable angle as measured through an arc ofthe wedge; a second wedge located opposite the wedge; and an axle towhich the wedge is attached, the axle capable of rotating such that thewedge rotates around a pivot point defined by the axle; wherein thevariable-wedge rotating-disk attenuator is located such that it affectsthe intensity of a light beam transmitted into an eye.
 7. (canceled) 8.A variable-wedge rotating-disk attenuator for use in an ophthalmicendoilluminator comprising: a first spine, the approximate center ofwhich is located at a pivot point; a second spine, the approximatecenter of which is located at the pivot point, the first and secondspines being independently rotatable; and a substantially opticallyopaque material located between the first and second spines, thesubstantially optically opaque material forming two wedges, each wedgecapable of being adjusted, the two wedges located opposite each otherwith respect to the pivot point; wherein the two wedges are rotated suchthat they attenuate the intensity of a light beam transmitted into aneye.
 9. The variable-wedge rotating-disk attenuator of claim 8 furthercomprising: a first axle to which the first spine is attached, the firstaxle located along a line containing the pivot point that issubstantially perpendicular to the first spine; and a second axle towhich the second spine is attached, the second axle located along a linecontaining the pivot point that is substantially perpendicular to thesecond spine.
 10. The variable-wedge rotating-disk attenuator of claim 9further comprising: a first motor connected to the first axle, the firstmotor for rotating the first axle; and a second motor connected to thesecond axle, the second motor for rotating the second axle.
 11. Thevariable-wedge rotating-disk attenuator of claim 10 further comprising:a controller for controlling the operation of the first and secondmotors wherein the controller operates the first and second motors atthe same rotation rate but out of phase with each other.
 12. Thevariable-wedge rotating-disk attenuator of claim 11 wherein an amountthat the first and second motors are out of phase corresponds to a sizeof the two wedges.
 13. The variable-wedge rotating-disk attenuator ofclaim 8 wherein the two wedges are located such that the attenuator isbalanced about the pivot point.
 14. The variable-wedge rotating-diskattenuator of claim 8 wherein the two wedges can be adjusted to an anglein the range of almost zero degrees to 180 degrees.
 15. A variable-wedgerotating-disk attenuator for use in an ophthalmic endoilluminatorcomprising: a first spine, the approximate center of which is located ata pivot point; a second spine, the approximate center of which islocated at the pivot point, the first and second spines beingindependently rotatable; a substantially optically opaque materiallocated between the first and second spines, the substantially opticallyopaque material forming two wedges, each wedge capable of beingadjusted, the two wedges located opposite each other with respect to thepivot point; a first axle to which the first spine is attached, thefirst axle located along a line containing the pivot point that issubstantially perpendicular to the first spine; a second axle to whichthe second spine is attached, the second axle located along a linecontaining the pivot point that is substantially perpendicular to thesecond spine; a first motor connected to the first axle, the first motorfor rotating the first axle; a second motor connected to the secondaxle, the second motor for rotating the second axle; and a controllerfor controlling the operation of the first and second motors; whereinthe controller operates the first and second motors at the same rotationrate but out of phase with each other to cause the variable-wedgerotating-disk attenuator to affect the intensity of a light beamtransmitted into an eye.
 16. The variable-wedge rotating-disk attenuatorof claim 15 wherein an amount that the first and second motors are outof phase corresponds to a size of the two wedges.
 17. The variable-wedgerotating-disk attenuator of claim 15 wherein the two wedges are locatedsuch that the attenuator is balanced about the pivot point.
 18. Thevariable-wedge rotating-disk attenuator of claim 15 wherein the twowedges can be adjusted to an angle in the range of almost zero degreesto 180 degrees.
 19. The variable-wedge rotating-disk attenuator of claim15 further comprising: a third spine spine, the approximate center ofwhich is located at the pivot point, the third spine rigidly connectedto and perpendicular to the first spine, the third spine connected tothe first axle; a fourth spine, the approximate center of which islocated at the pivot point, the fourth spine rigidly connected to andperpendicular to the second spine, the fourth spine connected to thesecond axle; and a substantially optically opaque material locatedbetween the third and fourth spines, the substantially optically opaquematerial forming third and fourth wedges, each third and fourth wedgecapable of being adjusted over an angle, the third and fourth wedgeslocated opposite each other with respect to the pivot point.